JPS59215973A - Variable displacement hydraulic rotary machine of tilting cylinder block type - Google Patents

Abstract

PURPOSE:To decrease a leak of hydraulic operating fluid, by interposing a seal piston between a selector valve plate and a casing and forming pressure receiving surfaces on the seal piston so as to increase pressing force of the seal piston by the hydraulic pressure acting on said surface. CONSTITUTION:In the case of a hydraulic rotary machine in which a selector valve plate 27 is supported to the end face of a cylinder block 4 fitting pistons 6 into plural cylinders 5... formed in the inside, a seal piston 21 is provided between the selector valve plate 27 and a head casing 23. This seal piston 21 forms in its one side a pair of fitting protrusive parts 22A, 22B to be slidably fitted to recessed parts 24A, 24B formed in the head casing 23, and oil chambers 25A, 25B are formed to be partitioned in an end side of the fitting protrusive part while the end face of the fitting protrusive part serves as pressure receiving surfaces 34A, 34B. Then if the pressure in either one of a suction port 28 or a discharge port 29 increases to a high level, the seal piston 21 is urged to a side of tht selector valve plate 27 by pressurized oil acting on the pressure receiving surfaces 34A, 34B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a diagonal shaft type hydraulic pump having a variable capacity mechanism;
The present invention relates to a hydraulic rotary machine used as a hydraulic motor.

1 to 3 show a hydraulic pump as a variable displacement oblique shaft type hydraulic rotating machine according to the prior art.

First, in FIGS. 1 and 2, l is a casing forming the main body of the hydraulic pump, 2 is a rotating shaft protruding into the casing 1, and 3 is a drive disk fixed to the rotating shaft 2. are shown respectively. 4 indicates a cylinder block, and inside the cylinder block 4 there are a plurality of cylinders 5.
,5. ... are bored in the axial direction, and a piston 6 is fitted into each cylinder 5 so as to be able to reciprocate. A connecting rod 7 is attached to each piston 6, and each connecting rod 7 is swingably supported by the drive disk 3. Reference numeral 8 denotes a switching valve plate in which a pair of layered suction and exhaust ports (9, 10) are bored, and one side of the switching valve plate 8 is connected to the cylinder block 4.
The opening 9A of the suction/exhaust port 9.10 is in contact with the distal end surface of the 1. A pair of rectangular port forming portions 8A and 8B are formed to surround the OA, and each of the boat forming portions 8A and 8B is connected to a sliding surface 12 formed on the head casing 11 that covers the tip of the casing 1. They are slidably abutted. The head casing 11 also has suction and exhaust passages 1 that communicate with the suction and exhaust ports 9 and 10 of the switching valve plate 8, respectively.
3.14 is drilled. The switching valve plate 8 can be changed in tilt by sliding along the sliding surface 12 of the head casing 11, and regardless of the tilting position of the switching valve plate 8, the suction/exhaust port) 9.10 Suction and exhaust passage 1
3.14 Due to the necessity of constant communication with the suction/exhaust port) 9.1
The openings 9A and IOA to the sliding surface 12 of 0 are long grooves in the direction in which the switching valve plate 8 is tilted. Further, reference numeral 15 denotes a tilting control member for tilting and displacing the cylinder block 4 with respect to the rotating shaft 2 together with the switching valve plate 8, and the tilting control member 15 is formed of a cylinder piston mechanism built into the head casing 11. .

The hydraulic pump according to the prior art has the above-mentioned configuration, and its operation will now be described in the case where port 9 of the suction/discharge ports 9 and 10 is used as the suction port and port 10 is used as the discharge port.

First, when the rotating shaft 2 is rotated, the cylinder block 4 is rotated via the connecting rod 7 supported by the drive disk 3. If the rotation center line of the cylinder block 4 is inclined at an inclination angle θ with respect to the center line of the rotation shaft 2 as shown in FIG. reciprocate. During the half-rotation period in which the piston 6 extends from the cylinder 5, the cylinder 5 communicates with the suction port 9 of the switching valve plate 8, and the suction stroke in which hydraulic oil is sucked into the cylinder 5 from the suction port 9 (5). becomes. On the other hand, during the half-turn when the piston 6 enters the cylinder 5, the cylinder 5 is switched to a state in which it communicates with the discharge port 10, and the hydraulic oil in the cylinder 5 is pressurized and discharged to the discharge port 10 during the discharge stroke. That's it. The pump action is performed by repeating the suction stroke and the discharge stroke in this manner.

In order to change the capacity of the pump, the cylinder block 4 is rotated by driving the tilt control member 15 and sliding the switching valve plate 8 along the sliding surface 12. Bye. As a result, the tilt angle θ between the rotational center line of the cylinder roller 4 and the center line of the rotating shaft 2 changes, and the stroke amount of the piston 6 also changes.

However, in the hydraulic pump operated as described above, since the switching valve plate 8 is in contact with the sliding surface 12 of the cylinder block 4 and the head casing 11, there is a gap between the respective contact parts. It is necessary to make sure that the high pressure oil does not leak from the north.

(6) By the way, during the operation of the hydraulic mulch pump, the hydraulic pressure inside the pump causes damage between the cylinder block 4 and the switching valve plate 8 and between the switching valve plate 8 and the sliding surface of the head casing 11. A pressing force and a separating force act.

The pressing force of the cylinder block 4 against the switching valve plate 8 and the pressing force of the switching valve plate 8 against the sliding surface 12 are generated by the hydraulic pressure within the cylinders 5, and are determined by the number of cylinders 5 and their cross-sectional area. be done.

On the other hand, the opening force is generated by the hydraulic pressure in the suction/discharge ports 9 and 10, and depends on the opening area of each of the two ports 9 and 10 to the cylinder block 4 and the sliding surface 12.
The opening force between the switching valve plate 8 and the switching valve plate 8 and the opening force between the switching valve plate 8 and the sliding surface 12 are determined. Therefore, by making this opening force smaller than the pressing force, the switching valve plate 8 is brought into close contact with the cylinder block 4 and the sliding surface 12 of the head casing 11. Here, in order to prevent an increase in the opening force due to leakage of hydraulic oil at the contact portion between the switching valve plate 8 and the sliding surface 12, the switching valve plate 8 is arranged as shown in FIG. , each having width a1 length b, bow) 9
．． Rectangular port forming portions 8A and 8B surrounding 10
are formed, and the shape is such that only the respective port forming portions 8A and 8B abut against the sliding surface 12.

The width a and length b of the port forming portions 8A and 8B described above are regulated by the relationship between the opening force and the pressing force, and cannot be set freely, so there are disadvantages that cause the following inconveniences. be. First, the width a of the I-toe forming portions 8A and 8B is a factor that determines the passage cross-sectional area of the suction and exhaust passages 13 and 14, and the passage cross-sectional area is made as large as possible in order to reduce pressure loss. There is a need to. However, as mentioned above, since the width a is regulated by the separation force, it is impossible to increase it to reduce the pressure loss.

Further, the length b of the port forming portions 8A, 8B is a factor that determines the tilting range of the cylinder block 4, and if the length b is restricted, it will not be possible to have a large tilting range. That is, the hydraulic rotating machine according to the prior art described above has the disadvantage that at least one of pressure loss reduction and tilting range must be sacrificed to some extent in order to avoid increasing the separation force.

The present invention has been made in view of the above points, and by increasing the pressing force between the switching valve plate and the head casing, the opening area of the opening of the suction/exhaust port to the head casing can be increased. It is an object of the present invention to provide a variable capacity oblique shaft type hydraulic rotating machine as described above.

The configuration adopted by the present invention to achieve the above object is as follows:
A seal piston is interposed between the switching valve plate and the casing, and a pressure-receiving surface is formed on the seal piston to press the seal piston in the direction of contact with the switching valve plate or the casing. be.

Embodiments of the present invention will be described below with reference to FIGS. 4 to 9.

First, FIGS. 4 to 6 show a first embodiment of the present invention, and in these figures, the same components as in FIGS. shall be. 21 indicates a seal piston (9), and the seal piston 21 has a pair of fitting protrusions 22A and 22B formed on one side thereof, and each of the fitting protrusions 2
2A and 22B are slidably fitted into recesses 24A and 24B formed in the head casing 23, respectively. The distal end surfaces of each of the fitting protrusions 22A, 22B are spaced apart from the recesses 24A, 24B, and an oil chamber 25A is formed between them.

25B is formed. On the other hand, a sliding surface 26 is formed on the other side of the seal piston 21, and a switching valve plate 27 is slidably abutted on the sliding surface 26. The switching valve plate 27
has an opening 28 for suction and exhaust ports 28 and 29 bored therein.
Port forming parts 27A and 27B are provided so as to surround A and 29A, and each port forming part 27A and 27B is connected to the sliding surface 2.
It is shown so that it can be slid along 6. Further, the seal piston 21 is provided with an i suction/discharge passage 30.31, and each suction/discharge passage 30.31 has an opening 28A at one end.
, 29A, and the other end is connected to the oil chambers 25A, 29A.
5B, respectively.

On the other hand, the head casing 23 has a suction and exhaust passage of 32° (10
) 33 is provided, and each suction and discharge passage 32.33 is connected to the oil chamber 25A.
, 25B, and are in communication with the suction and discharge passages 30 and 31, respectively. The end surfaces of the respective protrusions 22A and 22B of the seal piston 21 facing the oil chambers 25A and 25B become pressure receiving surfaces 34A and 34B, and the respective oil chambers 25
When the pressure inside A and 25B becomes high, this hydraulic pressure acts on the pressure receiving surfaces 34A and 34B, and the seal piston 21 is pressed in the direction of contacting the switching valve plate 27.

Further, 35 indicates a yoke as a support member for supporting the switching valve plate 27, and one end of the yoke 35 is connected to the bottle 36.
It is connected to the switching valve plate 27, and the other end is supported by the casing l via a support shaft (not shown). The yoke 35 has a function as a tilting drive member for tilting the pump, and also has a function as a positioning member in the axial direction of the switching valve plate 27. between the switching valve plate 27 or the switching valve plate 27
The switching valve plate 27 is configured to be prevented from being displaced in its axial direction due to the hydraulic pressure acting between the switching valve plate 27 and the seal piston 21.

Note that 37 in the figure indicates the protrusions 22A, 2 of the seal piston 21.
A sealing member interposed between the side surface of 2B and the side walls of recesses 24A and 24B is shown.

Although the present embodiment is constructed as described above, its operation as a hydraulic pump itself is not particularly different from that of the prior art described above.

However, when one of the suction and exhaust ports 28, 29 becomes high pressure, that pressure acts on either the pressure receiving surface 34A or 34B of the seal piston 21, causing the sliding surface 26 formed on the seal piston 21 to A pressing force is generated that presses the switching valve plate 27 in the direction of contact. On the other hand, suction/exhaust port)
A separating force is applied to the υ seal piston 21 in the direction of separating it from the switching valve plate 27 due to the hydraulic pressure in the high-pressure side ports 28 and 29. Furthermore, there is an opening between the switching valve plate 27 and the cylinder block 4, which is determined by the pressing force determined by the number and diameter of the cylinders 5 and the opening area of the suction and exhaust ports 28 and 29 toward the cylinder block 4. A separation force acts. However, since the switching valve plate 27 is positioned by the yoke 35, the hydraulic pressure acting between the cylinder block 4 and the switching valve plate 27 and the fluid pressure acting between the switching valve plate 27 and the seal piston 21 Due to the pressure, the fourth
All the forces pushing to the right and left in the figure are applied to the yoke 35.
Supported by Therefore, the pressing force and opening force between the cylinder pro 4 and the switching valve plate 27 and the pressing force and opening force between the switching valve plate 27 and the seal piston 21 do not affect each other. Therefore, in order to bring the switching valve plate 27 and the sliding surface 26 of the seal piston 21 into close contact, it is necessary to
The area of the pressure receiving surfaces 34A and 34B formed in the suction/discharge port)
The opening area of the openings 28A and 29A of 28.29 to the sliding surface 26 may be set larger than that of the openings 28A and 29A. As a result, the adhesion between the switching valve plate 21 and the sliding surface 26 is good υ, and the volumetric efficiency can be improved. Also, if the pressure receiving surfaces 34A and 34B are made as large as possible, this can be achieved. Opening of 28.29 (13) Shape of mouth portions 28A, 29A and port forming portion 27A
, 27B can be made larger, and the degree of freedom in setting the shape increases as shown in FIG. Therefore, if the width A is increased, the suction and exhaust passages 30, 31, 32,
The cross-sectional area of the passage 33 can also be increased, and pressure loss can be reduced. Therefore, the discharge efficiency at the discharge port is improved, the suction efficiency at the suction port is improved, and as a result, the torque efficiency is improved. As a result of improved suction efficiency, cavitation does not occur on the suction side even if the hydraulic oil tank that supplies hydraulic oil to the pump is not pressurized. Furthermore, when used as a hydraulic motor, the suction efficiency is good when the inertia of the member rotated by the motor acts as a pump, so cavitation is prevented from occurring.

On the other hand, if the length B of the port forming portions 27A and 27B is made longer, and the openings 28A and 29A are also made longer,
The tilting range can be increased (14). Therefore, since the stroke length of the piston 6 at the time of maximum tilting becomes longer, the cylinder volume per rotation can be increased. Further, when used as a hydraulic pump, it can be set to zero tilting state, allowing complete no-load operation, and can also be formed as a double tilting pump.

Next, FIGS. 7 to ffllO show a second embodiment of the present invention, and in these figures, the same components as in FIGS. shall be. However, in this embodiment, the Teha seal piston 41 is not provided in the Herad casing 42, but is provided on the switching valve plate 43 side. That is, the switching valve plate 4
3 has a recess 44 that is open toward the head casing 42 side.
A.

44B is formed, and the protrusions 45A and 45tl provided on the seal piston 41 correspond to the respective recesses 44A.

44B, and an oil chamber 46A between them.

46B is formed. And suction/exhaust ports) 47 and 48 are passages 47A, respectively.

47B and passages 48A and 48B, the passage 47
A, 48A is formed on the switching valve plate 43, and one end thereof is circumferential and opens at the sliding surface with the cylinder protrusion 4.
The other end opens into the oil chambers 4, 6A, and 46B, respectively.

The passages 47B and 48B are provided in the seal piston 41, and one end thereof opens into the oil chambers 46A and 46B, respectively. The other ends of each of the passages 47B and 48B are connected to the head casing 4 through port forming portions 41A and 41B.
The head casing 42 is open toward the sliding surface 49 of the head casing 42.
It is designed to constantly communicate with suction and exhaust passages 50 and 51 bored in the. Furthermore, each protrusion 45 of the seal piston 41
The end faces of the oil chambers 45A and 45B facing the oil chambers 45A and 46B are pressure receiving surfaces 52A and 52B, and the can pressure receiving surfaces 52A and 52B are
When hydraulic pressure is applied to the seal piston 41, the seal piston 41 is pressed in the direction of contacting the sliding surface 49, and a pressing force is generated therebetween.

Next, reference numerals 53 and 53 indicate guide walls as supporting members for the switching valve plate 43 that are installed upright on the head casing 42, and each guy V wall 53 is a side wall portion 53A that is provided parallel to the side of the switching valve plate 43. and a locking wall 53B protruding from the tip of each side wall portion 53A in a direction approaching each other.
It is positioned so as to be hugged by the f-wall 53. The side wall portion 53A functions as a tilt guide member that guides the switching valve plate 43 in the tilt direction. On the other hand, the locking wall 5
3B performs a positioning function to position the switching valve plate 43 so that it does not displace in its axial direction, and when the pump is in operation, the hydraulic pressure acting on the high pressure side port of the suction/discharge ports 47 and 48 of the switching valve plate 43 is As a result, the switching valve plate 43 is always pressed in the direction of contacting the locking wall 53B, so that the switching valve plate 43 is supported by the head casing 42 via the guide wall 53.

Note that 54 in the figure indicates the protrusions 45A and 4 of the seal piston 41.
This is a seal member provided between the side surface of 5B and the side walls of recesses 44A and 44B.

Even if configured as described above, the seal piston 41 and the sliding surface 4
The pressing force and separating force between the seal (17) and the pressure receiving area of the pressure receiving surfaces 52A and 52B of the piston 42 are transferred to the passage 47B of the ports 47 and 48.

By making the separation force larger than that determined by the shape of 48B, the adhesion is improved, and the effect is similar to that of the first embodiment described above. On the other hand, the switching valve plate 43 is pushed toward the cylinder 4 side by the hydraulic pressure in the high pressure side port of the intake/exhaust ports 47 and 48.
Since the switching valve plate 43 is locked to the guide wall 53, the pressing force between the cylinder block 4 and the switching valve plate 43 will not become excessive and the sliding resistance therebetween will not increase.

In each of the above embodiments, the case where the hydraulic rotary machine according to the present invention is used as a hydraulic pump has been described, but it goes without saying that it can also be used as a hydraulic motor. In addition, although the switching valve plate 27 and the seal piston 41 are provided with port forming portions 27A, 27B and 41A, 41B, these are provided to control the opening force, and it is not necessary to provide them. .

18) Furthermore, the sealing pistons 21.41 may be formed as a separate pair of sealing pistons for each intake/exhaust port 28 #29 and 47.48, respectively.

Furthermore, when used as a ponzo that tilts only in one direction or as a motor that rotates only in one direction, it is only necessary to form it so that it has a pressure receiving surface only on the high pressure port side, and there is a recess on the low pressure side. , it is not necessary to provide a seal piston protrusion and a pressure receiving surface.

As explained in detail above, the hydraulic rotating machine according to the present invention has a seal piston interposed between the switching valve plate and the casing, a pressure receiving surface is formed on the seal piston, and the hydraulic pressure acting on the pressure receiving surface is Since it is configured to increase the pressing force, it is possible to reduce leakage of hydraulic oil between the switching valve plate and the casing, improve volumetric efficiency, and have freedom in setting the port shape. Since the angle increases, the port shape can be designed to increase the tilting range and reduce pressure loss.

[Brief explanation of the drawing]

Figures 1 to 3 show the prior art, where Figure 1 is a longitudinal sectional view of a hydraulic rotating machine, Figure 2 is an enlarged view of the main part of Figure 1, and Figure 3 is a right side view of the switching valve plate. , Fig. 4 to Fig. 6 show the first embodiment of the present invention, Fig. 4 is a longitudinal sectional view of the main part of the hydraulic rotating machine, Fig. 5 is an explanatory diagram of the port shape, and Fig. 6 is a seal. The left side view of the piston, FIGS. 7 to 10 are the second views of the present invention.
Fig. 7 is a vertical sectional view of the main part of the hydraulic rotating machine;
8 is a left side view of the seal piston, FIG. 9 is a right side view of the seal piston, and FIG. 10 is a sectional view taken along the line X--X in FIG. 7. l Upper casing, 2...Rotating shaft, 4...Cylinder block, 5...Cylinder, 6...Piston, 21°41...Seal piston, 22A, 22I3, 45A
. 45B... Protrusion, 23.42... Head casing, 24A, 24B, 44A, 44B... Recess, 25A
. 25B, 46A, 46B...oil chamber, 28, 29. 47.48...Suction/exhaust port, 34A, 34B,
52A. 52B...Pressure receiving surface, 35...Yoke, 53...Guide wall. Figure 2 Figure 3 Figure 4 465- Figure 5 N Ward mountain guard

Claims (4)

[Claims] (1) A rotating shaft, a cylinder block that rotates together with the rotating shaft, and a switching valve plate that makes sliding contact with the cylinder block are provided in the casing, and together with the switching valve plate, the cylinder block is tilted with respect to the rotating shaft. In the variable capacity oblique shaft type hydraulic rotating machine that changes the capacity by changing the rotation,
A capacity characterized in that a seal piston is interposed between the switching valve plate and the casing, and the seal piston is formed with a pressure receiving surface that presses the seal piston in a direction in which it comes into contact with the switching valve plate or the casing. Variable oblique axis hydraulic rotating machine. (2) The seal piston is fitted into the casing and is provided in contact with the switching valve plate, so that the pressure receiving surface is pressed in a direction in which the seal piston contacts the switching valve plate. Claims characterized in (
1) The variable capacity oblique shaft hydraulic rotating machine as described in item 1). (3) The seal piston is fitted into the switching valve plate and is provided in contact with the casing, so that the pressure receiving surface is pressed in a direction in which the seal piston contacts the casing. A variable capacity oblique shaft type hydraulic rotating machine according to claim (1). (4) The variable capacity oblique shaft type % type according to claim (1), characterized in that the switching valve plate is provided with a support member for supporting the switching valve plate on the casing.